This invention relates to a metal lead frame on which electrical components are to be assembled and more particularly to such a lead frame having attached thereto an exothermically alloyable fuse strand.
It is well known to mount electrical components to lead frames in the manufacture of packaged electrical components. In the U.S. Pat. No. 4,107,762, issued Aug. 15, 1978 and assigned to the same assignee as is the present invention, a method is disclosed by which a lead frame could have been employed for packaging a fused solid electrolyte capacitor including a series connected fuse. The fuse is a short length of a bimetal exothermically alloyable strand connected in the package between the cathode terminal and the cathode of the encapsulated capacitor body.
Such an elemental bimetal strand is described in the U.S. Pat. No. 2,911,504 issued May 15, 1958. One end of the elemental fuse strand is stripped of one of its fuse metal components so that a weld can be made at that one fuse strand end between the cathode terminal and the other fuse metal of that one fuse strand end. The other fuse strand end in this case is soldered to the cathode-counter electrode of the capacitor body. In the making of both joints, care must be taken that the temperature of the fuse strand not exceed that which would initiate exothermic alloying and fusing of the elemental fuse strand. Alternatively, the use of a metal loaded resin is suggested for making these fuse-end connections.
It is an object of this invention to provide a simpler, more reliable method for attaching exothermically alloyable fuse stands to a lead frame.